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Ambr MCP Server

answering

Ambr is answering right now. Last checked 1 min ago. It exposes 7 tools.

Ricardian contracts for AI agents — dual-format, SHA-256 bound, legible by construction.

The linked repository no longer exists on GitHub — it was deleted or made private.

Uptime history 91 days of history · worst day 0%
91 days agonow
100.0%
Uptime 24h
92 of 92 checks
7
Tools
read from the server
173 ms
Response time
average over 24h
open, no key
Access
streamable-http

What changed 7

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 25 August 2026. No other catalogue keeps this.

6 Nov a tool appeared ambr_check_transaction
6 Nov a tool description was rewritten ambr_create_contract
6 Nov a tool changed the parameters it asks for ambr_create_contract
29 Oct a tool description was rewritten ambr_create_contract
29 Oct a tool changed the parameters it asks for ambr_create_contract
25 Aug a tool description was rewritten ambr_create_contract
25 Aug a tool changed the parameters it asks for ambr_create_contract

Ambr does not always answer

Over the last week it answered 59.1% of our checks. We check every 15 minutes, so you hear about the next outage within the hour — not from your users.

Three servers free · no card

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 1 min ago.

run in your terminal
claude mcp add ambr-mcp-server --transport http https://getamber.dev/api/mcp
Settings → Connectors → Add custom connector, then paste this address
https://getamber.dev/api/mcp
~/.codex/config.toml
[mcp_servers.ambr-mcp-server]
url = "https://getamber.dev/api/mcp"
.cursor/mcp.json
{
  "mcpServers": {
    "ambr-mcp-server": {
      "url": "https://getamber.dev/api/mcp"
    }
  }
}
.vscode/mcp.json
{
  "servers": {
    "ambr-mcp-server": {
      "type": "http",
      "url": "https://getamber.dev/api/mcp"
    }
  }
}

Available tools 7

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

ambr
ambr_agent_handshake
Initiate a handshake on a contract on behalf of your delegating principal. Requires an API key with an active delegation (principal wallet registered via /api/v1/delegations). Records the agent's intent to accept, reject, or request changes on the contract. The principal must separately approve via wallet signature on the Reader Portal. Args: - contract_id (string, required): Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID - intent (string, required): "accept" | "reject" | "request_changes" - message (string, optional): Note for the counterparty - visibility_preference (string, optional): "private" | "metadata_only" | "public" | "encrypted" Returns: Handshake status and next steps for principal approval. Legibility: the handshake itself is auditable — delegation scope, agent identity, and principal approval are recorded alongside the contract hash.
ambr_check_transaction
Check one payment against what an agreement allows. Advisory only: Ambr compares what you report with the agreement's terms; it does not authorize, block or see payments, and in_scope is not an approval or a guarantee. Tests the payment against the agreement's status, validity window, currency, per-transaction limit, monthly limit, approved categories, enumerated actions and approval threshold. If the agreement was amended, the newest approved version is checked. Free: no credits are burned. Ambr does not hold funds or track spend, so the monthly limit is checked only when you pass period_spent. A rule the agreement sets no limit for comes back as not_evaluated, never as a pass. If a rule has a limit but you did not send what it needs (category, action, currency, period_spent), the verdict is "incomplete", not "in_scope". Send everything the agreement limits. Access: a public contract is open to anyone; otherwise use the creator's API key or pass a share_token. Args: - contract_id (string, required): Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID - amount (number, required): payment amount, zero or more - currency (string, optional): e.g. "USD" - category (string, optional): spending category - action (string, optional): the action the agent is taking - period_spent (number, optional): already spent this month, to check the monthly limit - share_token (string, optional): share token for a private contract Returns: verdict ("in_scope" | "out_of_scope" | "incomplete" | "needs_approval"), the per-rule checks, plain-language reasons, and the contract that was checked (contract_id, effective_contract_id, sha256_hash, reader_url).
ambr_create_contract
Generate a Ricardian Contract from a template. Creates a dual-format contract (human-readable legal text + machine-parsable JSON) using AI, linked by SHA-256 hash. The contract is stored on Ambr and accessible via the Reader Portal. Requires a valid API key (X-API-Key header on the HTTP request) with available credits. Use ambr_list_templates first to discover templates and their required parameters. Args: - template (string, required): Template slug (e.g. "d1-general-auth") - parameters (object, required): Template-specific parameters matching the schema - principal_declaration (object, required): { agent_id, principal_name, principal_type } - principal_wallet (string, optional): the deploying party's own wallet. It must differ from the counterparty wallet in parameters (same_wallet_both_parties otherwise); left out, the first wallet that signs fills the principal side - parent_contract_hash (string, optional): SHA-256 hash of a contract you created, which this one is created under (its oversight threshold then applies). Not for amendments: propose those with POST /api/v1/contracts/{id}/amend - oversight_threshold_usd (number, optional): spending level above which work created under this contract needs human approval. Children exceeding it halt at awaiting_principal_approval. Returns: - contract_id: Unique ID (e.g. "amb-2026-0042") - sha256_hash: SHA-256 hash for verification - status: Contract status - reader_url: URL to view in Reader Portal - credits_remaining: Remaining API credits Legibility: Output is dual-format by construction and replayable to the original SHA-256 hash — the basis of Ambr's legibility guarantee.
ambr_get_contract
Retrieve a contract by ID, SHA-256 hash, or UUID. With a valid API key (contract creator): returns the full contract including human-readable text, machine-readable JSON, status, and principal declaration. Without authentication: returns metadata only (contract_id, status, hash, dates). Supports three lookup formats: - Contract ID: "amb-2026-0042" - SHA-256 hash: 64-character hex string - UUID: Standard UUID format Args: - id (string, required): Contract ID, SHA-256 hash, or UUID Returns: Full contract (if authorized) or metadata-only response. Legibility: retrieval preserves the dual-format pairing — prose and JSON always replay to the same SHA-256.
ambr_get_contract_status
Check the status of a contract and its amendment chain. Returns the current status and any linked amendments (parent or child contracts). Useful for verifying if a contract is active, amended, or terminated. Args: - id (string, required): Contract ID, SHA-256 hash, or UUID Returns: - contract_id, status, created_at - amendment_type, parent_contract_hash - amendments: Array of child contracts (if any) Legibility: amendments are bilateral and themselves dual-format — the chain stays legible from original through every revision.
ambr_list_templates
List available contract templates on Ambr. Returns all active Ricardian Contract templates with their slugs, names, descriptions, categories, parameter schemas, and pricing. Use this to discover which templates are available before creating a contract with ambr_create_contract. No authentication required. Returns: Array of template objects with slug, name, description, category, parameter_schema, price_cents, and version fields. Legibility: templates are the parameter schema for the dual-format contracts you create — starting here keeps your request conformant and your output defensible.
ambr_verify_hash
Verify a contract's SHA-256 hash to confirm document integrity. Checks whether the provided hash matches a contract stored on Ambr. Returns verification status, contract metadata, and Reader Portal URL if found. Args: - hash (string, required): SHA-256 hash (64-character hex string) Returns: - verified: boolean - contract_id: string (if found) - status: string (if found) - reader_url: string (if found) Legibility: verification is the point at which legibility becomes provable — matching hash means the prose a human reads and the JSON a machine parses are the same document that was originally signed.

Endpoints

URLTransportStateLatencyChecked
https://getamber.dev/api/mcp streamable-http answering 91 ms 1 min ago

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Ambr — questions

Answers built from our own checks of this server.

What can Ambr do?
It exposes 7 tools, read directly from the server on our last check. Among them: ambr_agent_handshake, ambr_check_transaction, ambr_create_contract, ambr_get_contract, ambr_get_contract_status, ambr_list_templates and 1 more. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →
Is Ambr working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 92 of 92 checks got a reply (100.0%), average response time 173 ms. The bar chart above shows every period we have measured.
Is Ambr still maintained?
The linked repository no longer exists on GitHub — it was deleted or made private. We show this because it changes what you can expect: an unmaintained server may keep answering for months and then stop without warning.
How do I connect Ambr?
Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.
Does Ambr need an API key?
No. Ambr completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 7 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is Ambr?
It answers our handshake in 173 ms on average, which is faster than 75% of all working MCP servers we measure. That puts it in the quick quarter of the ecosystem. The comparison comes from our own checks across the whole registry, every 15 minutes.